BMT Group's robotic fish have received a lot of attention due to their environmental mission, but you really can't ignore the fact that they look and swim so much like actual fish. Don't be fooled: This isn't just window dressing for the media. Their very design depends on biomimetic principles.

Biomimicry plays a role in many cutting-edge engineering projects, but it depends on a rather simple proposition: Why waste years of laboratory time trying to overcome a design obstacle when nature has already knocked it out of the park? Really, what human team of developers can rival millions of years of evolution? If you want to fly, look to the birds. If you want to superheat a liquid or climb walls, study how organisms achieve these ends. Sure enough, if you want to create an energy-efficient, autonomous aquatic robot, look no further than the denizens of the ocean. (Read How Biomimicry Works to learn more.)

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Efficiency was key to the developers because each robot needed to not only navigate an underwater environment on its own, but also operate for hours on battery life. While tethered remotely operated vehicles (ROVs) have proven invaluable to underwater exploration, their clunky designs are far from efficient, often depending on surface generators and umbilical cords. Fortunately for the team of designers at the University of Essex, energy efficiency is one of nature's specialties.

By employing the same movement mechanics as its organic counterpart, the robotic fish is able to squeeze eight hours of operation out of its battery life. When levels begin to dip, the bot returns to a central recharging hub to rest up for the next big day of pollution hunting.

Each robotic fish sniffs out trouble with an array of tiny chemical sensors capable of detecting dissolved contaminants, as well as those pooled on the surface of the water. As they make these discoveries, the robots continually send all the data back to the central hub with ultrasonic WiFi transmitters and receivers. The fish also can keep in touch with each other using these gadgets. All this adds up to an expanding, real-time view of an area's waterborne pollution, complete with chemical analysis and clues to where it may originate.

Before deployment, scientists wanted to ensure that the robot fish don't produce noise that might disrupt the natural environment. They already suspected that sharks would avoid the bot fish due to their electromagnetic fields. If the aquatic spies are a success in Gijon, then scientists hope to expand their operations around the world.

Of course, these fish aren't the only robots in the sea. On the next page, we'll look at some other varieties of pollution-sniffing underwater automatons.